title: Comparison of postoperative stability of three rigid internal fixation techniques after sagittal split ramus osteotomy for mandibular advancement.
abstract: BACKGROUND
  The aim of this investigation was to compare the skeletal stability of three different rigid fixation methods after mandibular advancement.
  
  
  METHODS
  Fifty-five class II malocclusion patients treated with the use of bilateral sagittal split ramus osteotomy and mandibular advancement were selected for this retrospective study. Group 1 (n = 17) had miniplates with monocortical screws, Group 2 (n = 16) had bicortical screws and Group 3 (n = 22) had the osteotomy fixed by means of the hybrid technique. Cephalograms were taken preoperatively, 1 week within the postoperative care period, and 6 months after the orthognathic surgery. Linear and angular changes of the cephalometric landmarks of the chin region were measured at each period, and the changes at each cephalometric landmark were determined for the time gaps. Postoperative changes in the mandibular shape were analyzed to determine the stability of fixation methods.
  
  
  RESULTS
  There was minimum difference in the relapse of the mandibular advancement among the three groups. Statistical analysis showed no significant difference in postoperative stability. However, a positive correlation between the amount of advancement and the amount of postoperative relapse was demonstrated by the linear multiple regression test (p < 0.05).
  
  
  CONCLUSIONS
  It can be concluded that all techniques can be used to obtain stable postoperative results in mandibular advancement after 6 months.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University - Unicamp, Brazil. Electronic address: fabio.sato@fop.unicamp.br.
authors.forename: Fábio Ricardo Loureiro
authors.initials: FR
authors.lastname: Sato
authors.affiliation: Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University - Unicamp, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Asprino
authors.affiliation: Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University - Unicamp, Brazil.
authors.forename: Roger William
authors.initials: RW
authors.lastname: Fernandes Moreira
authors.affiliation: Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University - Unicamp, Brazil.
authors.forename: Márcio
authors.initials: M
authors.lastname: de Moraes
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000473:pathology; D001860:Bone Plates; D001863:Bone Screws; D002508:Cephalometry / Q000379:methods; D002680:Chin / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery; D008334:Mandible / Q000473:pathology; D019186:Mandibular Advancement / Q000295:instrumentation* / Q000379:methods; D008875:Middle Aged; D059229:Osteotomy, Sagittal Split Ramus / Q000295:instrumentation* / Q000379:methods; D012008:Recurrence; D012189:Retrospective Studies; D012399:Rotation; D014716:Vertical Dimension; D055815:Young Adult
keywords: Mandibular osteotomy; Orthognathic surgery; Rigid internal fixation; Skeletal relapse